I think you've aready hit the nail on the head with your thoughts that this trip is about you & DH remembering it vs. a trip for her... I agree with PP on this subject to just let her dictate the trip. The 1st trip we took with the kids, I stated over & over that they dictated where we went - if they needed a rest, we rested; if we wanted to go right and they wanted left, we went left.
Some of the things I loved doing with the kids when they were that small...
- If you can make an ADR for the Crystal Palace breakfast for 1st thing in the morning so you can go into the park before it opens to the GP, do it. You can get pictures of her on Main Street/in front of the castle without all the crowds!
- An obvious one but have to mention - stroller, stroller, stroller!
- Another obvious one but needs to be said.... make sure you have your camera, batteries, more batteries, and more than 1 memory card. Be ready to take pictures at a moments notice. Take pictures of the good, the bad and the ugly! Why do I say it that way you ask.... well DD3 pitched a fit on the Ferry - she didn't like boats and didn't want to be on it. Stomped feet, arms crossed, puss on face. So what did I do, I snapped a bunch of pictures! That was one of the memorable events on that trip and it's hysterical to look back at that/those pictures - even though it wasn't all happy go lucky. DD now 12 even laughs about it.
- Plan on doing something low key mid-day/when she is used to napping. Some people like going back to their resort for a nap midday, we were never a fan of leaving the park and going back in but that was because we usually go off season and park hours are shorter. Some of the movie type stuff or shows are good for this... Hall of presidents, jungle cruise, Liberty Square Riverboat. Both kids would crash in the stroller for awhile and we would browse the shops, get something to eat, or just tuck ourselves off to the side for a little bit so they weren't so frazzled.
- She's a little girl so I'm gonna say it... Bibbidi, Bobbidi, Boutique - princess your girl up! I did it the "cheap" way with DD and bought her the Cinderalla dress, tiara, glitter for her hair, etc. before our trip but the pictures we got on the trip of DD in front of the castle, with Cinderella & Fairy Godmother are priceless! (She was Cinderella & DS was Dash from the incredibles for Halloween that year & we did the Halloween party at WDW)
- Look at a souvenier that you can do with both your daughter and future children (if your planning on having more down the road). We did the silhouette cutouts on Main Street (both kids) and they are hanging on the wall at home.
- Realize that your DD may or may not interact with characters. Some kids will only interact with the "human" characters vs ones like Mickey, Minnie etc. Also it could be just the appearance, colors, demeanor of some so don't rule out ALL characters if she balks at the 1st one.
Most of all... have fun & enjoy the trip! You will have so many sweet memories to last you forever! DH & I still talk about those moments and it's been more than 10 years since that 1st trip!